Florida's main private school voucher program will soon be open to middle-income families under a significant expansion signed into law Friday by Gov. Rick Scott.

TALLAHASSEE – Florida's main private school voucher program soon will be open to middle-income families under a significant expansion signed into law Friday by Gov. Rick Scott.

Scott approved the bill despite requests for veto from parent groups and the state's teachers union who said the expansion would come at the expense of traditional public schools. His decision to back the legislation could trigger a new round of lawsuits over the state's school choice programs.

The current program, which gives tax credits to businesses that pay for vouchers, serves nearly 60,000 families, most of whom attend religious schools. But the new law would broaden who is eligible to participate, which will help push the cost of the program beyond the current total of nearly $300 million.

The current program is limited to low-income families. But starting in 2016, families who earn more than $60,000 a year could receive partial scholarships. U.S. Census data estimates that the 2012 median household income in the state was just more than $47,000.

A spokesman for Step Up for Students, the main organization that hands out vouchers, said that based on current applications, the group will wind up serving as many 68,000 students in the coming school year.

Additionally, the new law (HB 850) removes a requirement that students attend a public school before becoming eligible for a voucher. The measure also creates "personal learning scholarship accounts" which help parents of disabled children get additional services for their children.

School choice advocates, including former Gov. Jeb Bush, hailed Scott's decision to approve the bill that had been a top priority of House Speaker Will Weatherford.

"Florida is giving families the ability to achieve more successful outcomes for their children," Bush said in a statement. It was under Bush that Florida's first established the tax credit scholarship program that is being expanded.

It was Bush's first voucher program — which offered them to students in failing schools — that sparked a legal battle that resulted in a state Supreme Court ruling declaring the vouchers unconstitutional.

That ruling did not apply to the tax credit scholarship program, but Joanne McCall, vice president of the Florida Education Association, said the group now is reviewing whether to challenge it in court.

"Instead of investing to make every public school as good as it can be, the Legislature and the governor divert a rapidly growing chunk of taxpayer dollars into these voucher schools and the groups that run them," McCall said in a statement.